Survivability enhancement is a well-known objective for armored vehicles or fixed or mobile armored structures in a combat or other high threat environment. If a high-energy projectile strikes a vehicle, the survivability of the occupants and the vehicle can be compromised by the release of spall, which is a spray of high velocity metallic or ceramic debris into the vehicle's interior. Vehicles, ships, aircraft, or structures in a high threat environment are therefore frequently equipped with a spall liner, which is designed to suppress the spall generated when a projectile penetrates the vehicle's interior.
U.S. patent application Ser. No. 11/881,863, filed on Jul. 30, 2007, the entire contents of which are incorporated herein in their entirety by reference thereto, disclosed a ballistic resistant panel that significantly improved threat performance by providing a strike face consisting of a compressed stack of interleaved layers of non-fibrous ultra high molecular weight polyethylene tape. The non-fibrous ultra high molecular weight polyethylene tape was TENSYLON® produced by BAE Systems Tensylon High Performance Materials, Inc., Monroe, N.C. The strike face, which formed at least 25% by weight of the entire panel, was compressed together with a backing layer of cross-plied fibers embedded in resin. Two types of cross-plied fibers were evaluated in the backing layer, including aramid and ultra high molecular weight polyethylene fibers. It was found that several adhesives are acceptable for adhering together cross-plied layers of Tensylon tape and that the level of adhesive required for adhering the layers of Tensylon tape was significantly less than for comparable layers of high modulus fibers.
Although the ballistic resistant panel with improved strike face disclosed in the aforementioned patent application exhibited good resistance against threats, continued tests have provided unexpected advantageous results. These unexpected results indicate that a further reduction in the ratio of strike face containing Tensylon tape, to backing containing high modulus polyethylene fibers, provides an increase in survivability.